Effect of varying crude protein levels on the performance and carcass characteristics of broiler chicken in the humid tropics

Abstract

This study was conducted to determine the effect of varying crude protein (CP) levels on the performance and carcass characteristics of broilers. In a 56 days feeding trial, 252 day old chicks were allotted to four dietary treatments. Each treatment consisted of 3 replicates of 21 birds each. Birds on each treatment (Trt) were fed varying CP (%) in a 3 stage feeding plan consisting of starter (0-3weeks), grower (3-6weeks) and finisher (6-8 weeks) and CP was reduced step wisely by 2% except in Trt IV as follow: Trt I, 25, 23 and 21; Trt II, 23, 21 and 19; Trt III 21, 19 and 17; Trt IV, 19 throughout the 3 stages and diets were based mainly on maize and soya bean. Daily weight gain and feed conversion were largely unaffected by the imposed dietary CP treatment during the starting, growing and finishing stages, but feed intake was significantly affected during the multi-stage feeding plan. Birds on Trt III, IV and IV had significantly (P<0.001) higher feed intakes during starter, grower and finisher phases respectively. However, the daily gain of birds on Trt III (21-19-17) was significantly depressed, when fed 17% CP at the finishing stage. Varying CP levels had no significant (P > 0.05) effect on dressing, breast and drumstick percentages determined (as % of live weight) at week 8. It was concluded that 19% CP may be sufficient for raising broilers with 36g daily gain from start to finish on corn-soya bean diet.